This invention relates to wire-drawing dies.
Heretofore, in the drawing of wire through one or more dies, a whole series of metallic dies or dies containing nibs, such as disclosed in U.S. Pat. Nos. 2,150,734 and 3,178,925 or die holders, such as disclosed in 3,109,663 have been employed for continually reducing the cross-sectional diameter of the wire being drawn.
Usually such dies may contain as many as one to fifteen die stands containing dies for continually reducing the cross-sectional diameter of the wire through drawing operations. It can be appreciated that if one of such dies overheats, chips, or in any manner some defect occurs in such die, that a defect will occur in the wire being drawn therethrough to thus render the wire worthless and unusable.
At the present time, lubricant is used to attempt to enable the wire to be forced or pulled through the die opening to lubricate for longer die life or to attempt to cool the die continuously as the wire is pulled or forced through.
Further, at the present time, when wire is being forced or drawn through dies, there is a large amount of dust, soot, or soap dust, scales generated when such wire is drawn or pulled through the die which constitutes a health hazard and further constitutes a serious problem of cleanliness since such scale dust usually is spread throughout the machinery in the wire-drawing plant.
At the present time the numeral draft of carbide dies begins in the range of 0.018 to 0.025 or 0.028 thousandths of an inch. This draft means that to begin wire-drawing operations, the first diameter opening through the die is from 0.018 to 0.025, etc. thousandths of an inch. Such numeral draft diameter indicates that it is necessary to have further die stands placed in the wire-drawing operations for continually attempting to reduce the size of the cross-sectional diameter of the wire and further also means that such wire-drawing operations have heretofore taken a longer time because of the number of wire-drawing stands through which the wire must pass until the proper cross-sectional diameter is obtained.
The prior art also discloses various compositions of non-metallic materials used in ceramic dies; however, such dies have also been disclosed, for example in U.S. Pat. No. 3,469,436 as die nibs or inserts in extrusion dies for the purpose of extruding metals through such combination dies. The application of this type of ceramic dies has been limited because of the brittle nature of the materials used and has often resulted in very short surface life for such dies which this causes increased costs throughout the industry.